Traditionally, commercial light housings, called “luminaires”, have been made with light gauge aluminum housings to reduce cost and weight. The problem with metal housings is that they block light from the fluorescent or LED bulbs inside.
One known improvement has been to use a translucent end cap either of glass or plastic with a high light transmission factor. One such example is shown in U.S. Pat. No. 2,288,606 to Callahan, with an end cap for a fluorescent lamp fixture that diffuses light from the ends of the fixture. This is achieved by extending a lower portion of the end cap inwardly from the end of the fixture under the elongated fluorescent lamp tube and under an inclined end portion of an internal reflector so that it “encloses” or overlaps the ends of the lamp tube. Some of the light emitted from the ends of the lamp tube is reflected off the bottom portion of the end cap and the inclined reflector against the side or face of the end cap and thus transmitted out the end of the fixture.
Another example is shown in U.S. Pat. No. 8,092,040 to Wu et al, with a fixture having an elliptical tapering cross-section. An elliptical end cap matching the fixture cross-section includes an opaque center and an angled translucent rim toward its outermost edge. This rim can transmit light in a semi-direct manner radially outward or horizontally from the lamps in the interior of the housing. The light transmitted from the translucent rim of the outer end cap appears to be indirectly received from the lamps through openings in an opaque inner end cap or bracket.
Another example is shown in U.S. Patent Application Publication No. US2014/0321121 A1 to Santoro et al, with an end cap optical lens assembly for a lighting fixture. The end cap assembly includes an outer lens, an inner lens, and a reflector. The lenses correspond to the fixture housing cross-section, and are rounded and angled downwardly from the housing at different angles to reflect and diffuse light received from the lamps.
While prior art end caps do provide additional light from the ends of their fixtures, this additional lighting is inefficient relative to the amount of light available for end lighting. Additionally, the prior art caps do not appear to provide any significant up-lighting immediately adjacent the fixture.